High Frequency Data Link (HFDL) is an ACARS communications protocol used to transmit AOC, CPDLC, and ADS messages between aircraft in flight and ground-based HFDL stations (downlink), using high frequency radio waves. The existing aeronautical HFDL system provides for a maximum data rate of 1.8 Kb/sec. Commercial and government users have requested high data rate (HDR) capability in excess of 1.8 Kbs, particularly for downlink (ex.—air-to-ground) use. Advanced waveforms can provide these higher data rates at signal/noise ratios comparable to existing HFDL waveforms as well as providing additional robustness under multipath conditions. However, re-engineering existing HFDL infrastructure (aircraft equipment as well as HFDL-enabled ground stations and their assigned frequencies) for new emission types and new frequency assignments may be a lengthy and expensive process. It may therefore be desirable to enable HDR capability, especially for downlink, over current HFDL equipment and within currently assigned ground station frequencies.